The objective of this proposal is to incorporate the recent advances in data collection techniques into the day-to-day operational procedures of protein crystallographic projects in Pittsburgh. The specific aim is to purchase a multiwire counter area detector system, designed by Xuong and his colleagues at UCSD. The detector system will be attached to a rotating anode x-ray generator which was recently purchased with joint funding from the NIH and the Medical Research Service of the Veterans Administration. For the detector system, the VA Medical Research will provide the space and utilities needed for its full operation and will pay for its service contract during the first year. After the first year, VAMC will share the service costs with the user groups as determined by an Advisory Committee. Within Pittsburgh's macromolecular crystallographic community, there are currently a total of 23 different protein crystal forms awaiting data collection. In some cases only native data need be collected to higher resolution. In other cases both native and derivative data must be collected, with the latter usually requiring the collection of numerous data sets before suitable derivatives are found. Recent developments in Pittsburgh have already greatly reduced the time and effort required to determine the phase information necessary for structure solutions. As a result of these developments, the rate-determining step in a structure determination experiment is now the data collection process. The acquisition of an area detector system in Pittsburgh would result in enhanced productivity for all researchers involved, since it would reduce the rate-determining step. The proposed detector system will be shared by eight ongoing group projects.